Event Processor

A Pacto contract for an event-driven service — a stateless consumer that processes messages from a message broker and exposes an HTTP health endpoint.

pactoVersion: "1.0"

service:
  name: order-processor
  version: 1.4.0
  owner: team/orders
  image:
    ref: ghcr.io/acme/order-processor:1.4.0
    private: true

interfaces:
  - name: order-events
    type: event
    visibility: internal
    contract: interfaces/order-events.yaml

  - name: health
    type: http
    port: 8080
    visibility: internal

configurations:
  - name: default
    schema: configuration/schema.json
    values:
      BROKER_HOST: rabbitmq.internal
      BROKER_PORT: 5672
      BROKER_CREDENTIALS: secret://vault/order-processor/broker-credentials
      DEAD_LETTER_QUEUE: orders.dlq
      MAX_RETRIES: 3

dependencies:
  - name: rabbitmq
    ref: oci://ghcr.io/acme/rabbitmq-pacto@sha256:abc123
    required: true
    compatibility: "^3.13.0"

runtime:
  workload: service

  state:
    type: stateless
    persistence:
      scope: local
      durability: ephemeral
    dataCriticality: medium

  lifecycle:
    upgradeStrategy: rolling
    gracefulShutdownSeconds: 60

  health:
    interface: health
    path: /health

  metrics:
    interface: health
    path: /metrics

scaling:
  min: 2
  max: 8

metadata:
  team: orders
  tier: standard
  consumer-group: order-processing

Key decisions

• type: event — declares that this service consumes events rather than serving HTTP/gRPC requests
• contract: interfaces/order-events.yaml — the event contract (e.g. AsyncAPI or custom schema) is bundled and versioned alongside the service
• dataCriticality: medium — event processing failures have moderate impact; dead-letter queues provide a safety net
• gracefulShutdownSeconds: 60 — allows in-flight messages to complete processing before shutdown
• Secret reference — broker credentials use secret:// so the platform injects actual credentials at deployment time